FireDAC Lost connection to MySQL server during query - mysql

I have two FireDAC connections on my application, one is intended to be used on a MySQL Server that is on LAN and store private data of the my shop (like sales, products, etc), and the another one is connected to a remote (internet) MySQL Server, and it randomly give me a exception
First chance exception at $745AA882. Exception class
EMySQLNativeException with message '[FireDAC][Phys][MySQL] Lost
connection to MySQL server during query'.
Is this a issue on FireDAC, my code or the remote MySQL Server?
Using NAVICAT software I have no problem.

This error usually occurs because the Internet Connectivity is not stable and connection closed during exchanging data
Sometimes you can solve this issue with increasing the connection Time-Out (and ReadTimeOut )
Sometimes this error occurs because you are trying to send or receive large amount of data like Blob fields and you should increase the max_allowed_packet variable of MySQL Server to solve the problem
The next suggestion for solving this problem is avoiding dns lookup by adding skip-name-resolve to the settings of your MySQL Server
The Main reasons of this problem is connection stability and MySQL Server Settings
If you have access to MySQL server and can change the settings, this link may be useful :
http://www.monitis.com/blog/101-tips-to-mysql-tuning-and-optimization/
You can find many articles about increasing performance of MySQL Server

Related

How to fix Named Pipes Provider, error: 40 - Could not open a connection to SQL Server?

I'm having trouble connecting or logging in to my SQL Server database. I had a previous working instance before, but I forgot the password and decided to just reinstall the whole thing since I don't have any data to lose. I realized that was a bad idea but now, each time I attempt to log in to my SQL Server, I get the following error message:
I tried to search for an answer, but it seems nothing is working. Here is what I tried so far:
Enabling the Named Pipes from the SQL Server Configuration Manager under the SQL Server Network Configuration tree item
I tried restarting the SQL Server item from the list of services in the Services application
I tried restarting everything in the SQL Server Configuration Manager that is related to my database or at least have my instance's name on it
There are other things that I tried which I fail to remember. Any help would be much appreciated.

How to close connection to a remote MySQL database?

I was testing my SpringBoot app which connects to a remote SQL database. I was also using MySQL workbench to view the tables. Then when I tried to run my app, it gave an error message as follows:
Data source rejected establishment of connection, message from server: "Too many connections"
I have tried restarting my PC but it still gives the same error. How can I solve it? I believe the previous connection was not properly closed. What can I do now?
The connections are automatically closed (or return to the connection pool) if you are using Spring Data Repository or JdbcTemplate. Your application may really need too many connections compared to your database limit, in that case you should check your database configuration. You can also check your connection properties in application.properties (pool size, idle time, timeout). Please add more details like code or configuration.

Ghost Blogging Platform Connection Reset Error

I am running Ghost as a web service on Microsoft azure. I am using MySql Database for storage instead of the default Sqlite. Every time i open the blog i get a Econnreset error with status as 500, and Sql query is being shown.
I have MySql Running in a virtual machine. But everything works out fine on refresh. I am also using connection pooling.
How to rectify this, or what can be the probable reason for Ghost to drop connection with database.
Solved the problem. Issue is with the underlying Knex MySql Driver. When the connection remains Idle Azure closes the connection, when the request is made again knex does not check if the connection is still there or not leading to Econnreset Error.
You can fix this by setting min number of connections to be zero in knex.
For more details follow this issue:
https://github.com/tgriesser/knex/issues/975
Is the mysql database hosted on another azure instance ?
If so you will need to make it available to the outside (Open the required ports).

A transport-level error has occurred when receiving results from the server [closed]

Closed. This question is not reproducible or was caused by typos. It is not currently accepting answers.
This question was caused by a typo or a problem that can no longer be reproduced. While similar questions may be on-topic here, this one was resolved in a way less likely to help future readers.
Closed 6 years ago.
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I'm getting a SQL Server error:
A transport-level error has occurred
when receiving results from the
server. (provider: Shared Memory
Provider, error: 0 - The handle is
invalid.)
I'm running Sql Server 2008 SP1, Windows 2008 Standard 64 bit.
It's a .Net 4.0 web application. It happens when a request is made to the server. It's intermittent. Any idea how I can resolve it?
The database connection is closed by the database server. The connection remains valid in the connection pool of your app; as a result, when you pickup the shared connection string and try to execute it's not able to reach the database. If you are developing Visual Studio, simply close the temporary web server on your task bar.
If it happens in production, resetting your application pool for your web site should recycle the connection pool.
Try the following command on the command prompt:
netsh interface tcp set global autotuning=disabled
This turns off the auto scaling abilities of the network stack
I had the same problem. I restarted Visual Studio and that fixed the problem
Transport level errors are often linked to the connection to sql server being broken ... usually network.
Timeout Expired is usually thrown when a sql query takes too long to run.
So few options can be :
Check for the connection in VPN (if used) or any other tool
Restart IIS
Restart machine
Optimize sql queries.
For those not using IIS, I had this issue when debugging with Visual Studio 2010. I ended all of the debugger processes: WebDev.WebServer40.EXE which solved the issue.
All you need is to Stop the ASP.NET Development Server and run the project again
If you are connected to your database via Microsoft SQL Server Management, close all your connections and retry.
Had this error when connected to another Azure Database, and worked for me when closed it.
Still don't know why ..
Look at the MSDN blog which details out this error:
Removing Connections
The connection pooler removes a connection from the pool after it has
been idle for a long time, or if the pooler detects that the
connection with the server has been severed.
Note that a severed connection can be detected only after attempting
to communicate with the server. If a connection is found that is no
longer connected to the server, it is marked as invalid.
Invalid connections are removed from the connection pool only when
they are closed or reclaimed.
If a connection exists to a server that has disappeared, this
connection can be drawn from the pool even if the connection pooler
has not detected the severed connection and marked it as invalid.
This is the case because the overhead of checking that the connection
is still valid would eliminate the benefits of having a pooler by
causing another round trip to the server to occur.
When this occurs, the first attempt to use the connection will detect
that the connection has been severed, and an exception is thrown.
Basically what you are seeing is that exception in the last sentence.
A connection is taken from the connection pool, the application does
not know that the physical connection is gone, an attempt to use it is
done under the assumption that the physical connection is still there.
And you get your exception.
There are a few common reasons for this.
The server has been restarted, this will close the existing connections.
In this case, have a look at the SQL Server log, usually found at:
C:\Program Files\Microsoft SQL Server\\MSSQL\LOG
If the timestamp for startup is very recent, then we can suspect that
this is what caused the error. Try to correlate this timestamp with
the time of exception.
2009-04-16 11:32:15.62 Server Logging SQL Server messages in file
‘C:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\LOG\ERRORLOG’.
Someone or something has killed the SPID that is being used.
Again, take a look in the SQL Server log. If you find a kill, try to
correlate this timestamp with the time of exception.
2009-04-16 11:34:09.57 spidXX Process ID XX was killed by
hostname xxxxx, host process ID XXXX.
There is a failover (in a mirror setup for example) again, take a look in the SQL Server log.
If there is a failover, try to correlate this timestamp with the time
of exception.
2009-04-16 11:35:12.93 spidXX The mirrored database “” is changing roles from “PRINCIPAL” to “MIRROR” due to
Failover.
Was getting this, always after about 5 minutes of operation. Investigated and found that a warning from e1iexpress always occurred before the failure. This apparently is an error having to do with certain TCP/IP adapters. But changing from WiFi to hardwired didn't affect it.
So tried Plan B and restarted Visual Studio. Then it worked fine.
On closer study I noticed that, when working correctly, the message The Thread '<No Name>' has exited with code 0 occurred at almost exactly the time the run crashed in previous attempts. Some Googling reveals that that message comes up when (among other things) the server is trimming the thread pool.
Presumably there was a bogus thread in the thread pool and every time the server attempted to "trim" it it took the app down.
You get this message when your script make SQL Service stopped for some reasons. so if you start SQL Service again perhaps your problem will be resolved.
I know this may not help everyone (who knows, maybe yes), but I had the same problem and after some time, we realized that the cause was something out of the code itself.
The computer trying to reach the server, was in another network, the connection could be established but then dropped.
The way we used to fix it, was to add a static route to the computer, allowing direct access to the server without passing thru the firewall.
route add –p YourServerNetwork mask NetworkMask Router
Sample:
route add –p 172.16.12.0 mask 255.255.255.0 192.168.11.2
I hope it helps someone, it's better to have this, at least as a clue, so if you face it, you know how to solve it.
I got the same error in Visual Studion 2012 development environment, stopped the IIS Express and rerun the application, it started working.
I had the same issue. I solved it, truncating the SQL Server LOG.
Check doing that, and then tell us, if this solution helped you.
For me the solution was totally different.
In my case I had an objectsource which required a datetimestamp parameter. Even though that ODS parameter ConvertEmptyStringToNull was true 1/1/0001 was being passed to SelectMethod. That in turn caused a sql datetime overflow exception when that datetime was passed to the sql server.
Added an additional check for datetime.year != 0001 and that solved it for me.
Weird that it would throw a transport level error and not a datetime overflow error.
Anyways..
In my case the "SQL Server" Server service stopped. When I restarted the service that enabled me to run the query and eliminate the error.
Its also a good idea to examine your query to find out why the query made this service stop
For me the answer is to upgrade the OS from 2008R2 to 2012R2, the solution of iisreset or restart apppool didn't work for me.
I also tried to turn of TCP Chimney Offload setting, but I didn't restart the server because it is a production server, which didn't work either.
We encountered this error recently between our business server and our database server.
The solution for us was to disable "IP Offloading" on the network interfaces.
Then the error went away.
One of the reason I found for this error is 'Packet Size=xxxxx' in connection string. if the value of xxxx is too large, we will see this error. Either remove this value and let SQL server handle it or keep it low, depending on the network capabilities.
It happened to me when I was trying to restore a SQL database and checked following Check Box in Options tab,
As it's a stand alone database server just closing down SSMS and reopening it solved the issue for me.
This occurs when the database is dropped and re-created some shared resources is still considering the database still exists, so when you re-run execute query to create tables in the database after it was re-created the error will not show again and Command(s) completed successfully. message will show instead of the error message Msg 233, Level 20, State 0, Line 0 A transport-level error has occurred when sending the request to the server. (provider: Shared Memory Provider, error: 0 - No process is on the other end of the pipe.).
Simply ignore this error when you are dropping and recreating databases and re-execute your DDL queries with no worries.
I faced the same issue recently, but i was not able to get answer in google.
So thought of sharing it here, so that it can help someone in future.
Error:
While executing query the query will provide few output then it will throw below error.
"Transport level error has occurred when receiving output from
server(TCP:provider,error:0- specified network name is no longer
available"
Solution:
Check the provider of that linked server
In that provider properties ,Enable "Allow inprocess" option for that particular provider to fix the issue.

A transport-level error has occurred... (Existing connection closed by the server) Sql Server 2008

I have a web application which is currently running on Windows XP operating system with SQL Server 2005 database and IIS 6.0.
Now, we are trying to upgrade it to IIS 7.0 on Windows Server 2008 and SQL server 2008 database.
When I run the application then it is throwing "A transport-level error has occurred when sending the request to the server. (provider: TCP Provider, error: 0 - An existing connection was forcibly closed by the remote host.)" randomly at different database calls.
I have verified using "sp_who" that only one connection which I am using is opened.
Can anyone tell me, what could be the cause of this issue?
This blog post by Michael Aspengren explains the error message "A transport-level error has occurred when sending the request to the server."
Maybe the database is set to auto-close? This used to be the default for databases created on the older MSDE/Express edition.
ALTER DATABASE YourDatabaseName SET AUTO_CLOSE OFF;
More:
The SQL Server 2005 Express Edition Overview states:
Features like Auto-Close and the ability to copy databases as files are enabled by default in SQL Server Express ...
I can't remember which service pack changed the default, but the New Database UI in the SP3 version of Management Studio Express defaults the Auto Close setting to false.
This is an error that occurrs when connecting to database due to a lower layer network-related error that you cannot handle from Sql Server.
It would be great that the API used to conenct handled this error but AFAIK it is not. The only way to solve this is to retry connecting to the database when this error occurrs.
You should try to reconnect at least a couple of times more to get sure that the error is not persistent and if it is the case then throw the exception. My experience tells me that trying to reconnect, the 99.9% of times you will succed.
Often, it's the database being offline/closed or the SQL Instance being restarted/offline
In my case. We have DELL R720, NICs are on board and PCI Broadcom NetXtreme Gigabit Ethernet cards. We run into two issues.
Network speed is very slow for HyperV VMs. The solution is to disable the "Virtual Machine queues" of the HyperV host Broadcom nic property windows. It is in the Advanced tab.
SQL client having this transport level issue. It only happened once in every 10-15 min. At the same time the RDP service kick out client from time to time also. The solution is to disable the "Large Send Offload V2" of the HyperV host Broadcom nic property windows. It is in the Advanced tab.
Check if you have MultipleActiveResultSets=true; set in your connection string.
Transport level errors are often linked to the connection to sql server being broken ... usually network.
Timeout Expired is usually thrown when a sql query takes too long to run. Is this the scenario in your case? Like stored proc taking too much time to execute or are there are batch jobs that are executed?
Use clearpool(urSQLconnection), along with dispose. This will clear the dirty connection. and you can open new connection.
Got this trying to execute commands from multiple threads on one connection object in .net, that was a stupid mistake. Locking it or using a separate connection per thread fixes that.
In my case it was McAffee that was pre-installed. Can tell if it was conflict with other solutions or not. The connection was on VPN, on WiFI. Maybe this will help someone in future.